Take a step back and look at each part of system.

1. Can you display a simple helloworld.htm file? If so, then IIS is working.
2. Can you display a .aspx file? The file should have a textbox and button. When you click the button, round-trip to the server can change the text in the text box. If this works, asp.net is working correctly.
3. If 1 & 2 work, it's an application problem. Are file/directory rights set properly? Are you impersonating? What account does asp.net run under and does it have proper rights to folders/files? Are you running under a custom app pool?

>Hi,
>
>I have been having a problem with new installation of an existing ASP.NET application on Windows 2008 R2, IIS. (Note that the same application runs well on some other customers' Windows 2008, IIS). The problem we are getting when running any .ASPX page (even simple Hello World) is:
>
>

>: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name 
>changed, or is temporarily unavailable.  Please review the following URL and make sure that it is spelled correctly. 
>

>
>We (I and the customer web admin) looked at all kinds of possible settings but can't seem to find a solution. Any setting you recommend we should look at? TIA.